This invention generally relates to a memory storage apparatus and, more particularly memory storage apparatus having power off control.
Owing to the rapid development of information technology (IT) for harmonizing computers, communications, and broadcasting, advanced electrical information equipment is being continuously introduced. These digital technology developments have allowed users to enjoy various benefits. Recently, once such digital technology development is the introduction of various portable storage apparatus capable of storing multi-media data that may be used by the public with the digital technology development. Such devices have been used in applications such as digital camcorders, digital cameras, MP3 players, digital audio tape recorders, cellular phones, and PDAs. In order to store data, they typically employ memory devices or micro hard disks. Types of mobile memory cards include multi-media cards, secure-digital cards, compact flash cards, universal serial bus (USB) flash disks, and memory sticks. These devices may be simple, sturdy and removable. The memory cards are increasingly useful in our information oriented society because they may store information in a small size device, maintain information even if their power supply is turned off, and may store a large amount of information.
The development of memory cards generally is based in the advent of personal computer (PC) cards. PC cards have been used in handheld devices, such as notebooks, as early as the late 1980's and typically were compliant with memory extension standards and the size of a conventional credit card. A series of industry “PC Card Standards” are defined by standards originally developed by the Japan Electronic Industry Development Association (JEIDA), which are now being promulgated by the Personal Computer Memory Card International Association (PCMCIA), Sunnyvale, Calif., U.S.A. A series of industry “PC Card Standards” was further internationally standardized by JEIDA and PCMCIA in 1995.
Historically, as digital cameras have been introduced recently, most of the cameras typically store data in a built-in memory, however, some such cameras use a PC card as a storage media. With the current trend toward miniaturization of handheld devices since about 1990, the PC card's size has become relatively large for some applications. As such, a need developed for a smaller, lighter memory card. One such memory card, a “Compact Flash” was developed by Sandisk Corporation. This compact flash product generally is compatable with the PC card interface. PC cards generally can be mounted in a slot by an adaptor. In addition, other memories may use a PC card adaptor, but there may be differences in use as the adaptor for the compact flash may be used as only a simple connector without a logical data conversion.
With the advent of the compact flash, many other companies entered the memory card market and additional micro memory cards have become introduced. For example. Toshiba introduced smart media (at that time (about 1995), referred to as a “SSFDC (Solid State Floppy Disk Card)). Sony introduced the memory stick in about 1997 and MMC (Multi-Media Card) products were announced by companies including Hitachi and San Media. Another example is the “SD memory Card” introduced by companies including Matsushita, Toshiba, and Sandisk about 1998. In about 1999, “Secure MMC” and “Magic Gate Memory.” which are subject to copyright protection, were announced by Hitachi and Sanyo, and Sony, respectively.
All mobile memory storage apparatus of above-mentioned generally require a power source for operation. The power may be supplied within a product by a power supply source. However, the power is generally supplied from a host connected to the memory storage apparatus. If the power is supplied from the host, the memory storage apparatus may be configured to address various potential problems. For example, the memory storage apparatus may suddenly be controlled from the host, or the power from the host may be cut off suddenly. In order to address such events, most current memory storage apparatus, as shown in FIG. 1, typically have a power-off recovery algorithm 50 that may be executed and/or stored in a controller 30.
A mobile memory storage apparatus 20 as illustrated in FIG. 1 includes a non-volatile memory 40 and the controller 30. The non-volatile memory 40 is a space for storing data, and the controller 30 controls read and write operations of the non-volatile memory 40. The power-off recovery algorithm 50 may be configured to respond to a sudden cut off of an external power supply to the apparatus 20. Even if power is abnormally cut off in the memory storage apparatus 20, the power-off recovery algorithm 50 may be operated so as to reduce the risk of or even prevent defects caused to data stored in the non-volatile memory 40 during power off.
The power-off recovery algorithm 50 may be performed repeatedly while the mobile memory storage apparatus 20 is in operation. As a result, the performance of the apparatus 20 may be degraded by diversion of resources from its memory storage operations. A firmware code that may be provided in a memory of the controller 30 or otherwise may also become more complex by adding additional software code for the power-off recovery algorithm 50. Moreover, due to an additional storage space for the power-off recovery algorithm 50, the amount of available storage capacity required in the controller 30 may be increased.